Sheet stacker

ABSTRACT

A sheet stacker in which a sheet feed conveyor is progressively moved upwardly as the height of a stack formed from the sheets discharged from the conveyor increases with the stack being deposited on a stack removal conveyor connected to the sheet conveyor through a motor driven friction roller which can be bodily moved with the roller locked in position to maintain the stack in alignment with the discharge end of the conveyor and with the roller being drivingly operable following stacking to convey the completed stack away from the stacking station.

United States Patent [72] Inventor Raymond L. R. Lucas Avenue de La Republique, Prechac, Gironde, France 21 Appl. No. 32,632

[22] Filed Apr. 28, 1970 [45] Patented Oct. 5, 1971 [32] Priority July 21, 1969 [3 3] France Continuation-impart of application Ser. No. 743,419, July 9, 1968, now Patent No. 3,549,144.

[54] SHEET STACKER 10 Claims, 1 Drawing Fig.

[52] US. Cl 271/68 [5l] B65h 29/50 [50] Field of Search 271/68, 86,

[56] References Cited UNITED STATES PATENTS 3,321,202 5/1967 Martin 27 l/68 3,549,144 12/1970 Lucas 271/68 Primary Examiner-Joseph Wegbreit Att0rney-Mason, Fenwick & Lawrence ABSTRACT: A sheet stacker in which a sheet feed conveyor is progressively moved upwardly as the height of a stack formed from the sheets discharged from the conveyor increases with the stack being deposited on a stack removal conveyor connected to the sheet conveyor through a motor driven friction roller which can be bodily moved with the roller locked in position to maintain the stack in alignment with'the discharge end of the conveyor and with the roller being drivingly operable following stacking to convey the completed stack away from the stacking station.

PATENTED UBT SIB?! INVENTOR ATTORNEY.

SHEET STACKER This application is a continuation-in-part of my earlier filed US. application filed on July 9, 1968, Ser. No. 743,419, now U.S. Pat. No. 3,549,144.

The present invention relates to an improvement in automatic sheet stackers of the type employed with planar articles such as corrugated cardboard, fiberboard or the like and includes a conveyor having one end pivotal about a fixed horizontal axis while the other end moves up and down in an arc of a circle in a vertical plane.

The parent application of which this application represents an improvement thereover, describes a sheet stacker employing a rigid frame upon which an endless sheet conveyor belt is supported on an elongated conveyor support frame for delivering the sheets to be stacked. The sheets are conveyed to a discharge head end of the conveyor and are then deposited on a vertical stack on a movable stack supporting carriage. Means are provided for adjusting the position of the supporting carriage so that the discharge end of the conveyor is always in vertical alignment with a given point on the carriage as the discharge end moves from its lower position to its upper position during the course of completion of a stack. Automatic means for positioning the stack carriage moves the stack carriage forwardly and backwardly in accordance with the horizontal position of the discharge end of the depositing conveyor.

Additionally, the device of the parent application employs a pair of circular plates each having an eccentric roller engaging the lower edge of the conveyor frame so that rotation of the circular plate serves to adjust the vertical height of the discharge end of the conveyor.

Also, the device of the parent application supports the stack on a horizontally movable carriage and the position of the stack carriage is specifically determined by a rod connected to a pivotable lever which is, in turn, pivotally connected to the conveyor support frame and which has a cam follower engageable with a cam mounted on the same shaft as the circular plate for adjusting the height of the discharge end of the conveyor.

The instant invention eliminates the use of circular plates, rollers, cams and the like of the type employed in the earlier filed application through the employment of hydraulic means for adjusting the vertical heightof the discharge end of the conveyor. The advantages of the instant system over the system of the parent application include the obtainment of a greater flexibility of control, ease of adjustment both as to amplitude of movement and speed of operation and a more simple and economical device both for manufacture and maintenance. Specifically, the present invention employs two hydraulic jack means having one end fixed to the main machine frame with the other end connected to a point on the longitudinal conveyor frame members supporting the sheet feeding conveyor. Extension and retraction of the jacks serves to lift and lower the discharge end of the conveyor for movement through the arc of a circle oriented in a vertical plane.

A stack receiving and removing conveyor supports the stacks as they are formed at a stacking station and includes a movable belt which is actuated for removing a completed stack from the stacking station. Moreover, a mechanical connection between the stacking conveyor support frame and the movable belt stack-receiving conveyor moves the belts during the course of a stacking operation backwards and forwards to maintain a predetermined portion of the belt in vertical alignment with the discharge end of the sheet feeding conveyor. More specifically, the means for adjusting the position of the stack receiving belt includes an L-shaped lever having a vertical arm connected to a roller mounted for horizontal displacement in a horizontal slide groove on the main frame of the machine. The roller is connected to a rod which is connected to the sheet conveyor supporting frame for movement therewith. Consequently, the reciprocal arcuate movement of the sheet conveyor supporting frame is converted into a rectilinear reciprocating movement of the roller along the horizontal slide groove.

The L-shaped lever also includes a horizontal arm on which a cylindrical friction drive roller is mounted for driven rotation or for locked nonrotative bodily displacement with the L- shaped lever. Moreover, the brake lock of the friction drive roller is deactivated upon actuation of an electric drive motor connected to the drive roller through a speed reducer for drivingly rotating the roller and causing a consequent movement of the stack receiving and removing belt. Therefore, it will be seen that the stack receiving and removing belt can be moved by either bodily displacement of the friction drive roller when the roller is locked against rotation or by rotation of the roller when it is driven by the roller drive motor. The drive roller is gravitationally urged into driving engagement with the top surface of the stack receiving and removing conveyor belt. Consequently, operation of the motor to rotate the drive roller serves to move the stack receiving and removing belt. The magnitude and direction of the belt displacement are controllably determined in order to maintain the stack in vertical alignment with the discharge end of the stacking conveyor as the stack is being formed.

The point of attachment of the roller-controlling rod to the pivotal conveyor supporting frames for the teeth to be stacked moves in an arc of a circle that is homothetic to the arc of the discharge end of the conveyor. The stack-receiving belt can be locked in position on its support rollers so that rotation of the friction drive roller and its associated motor etc., serves to move the stacker conveyor etc., which is supported by wheels longitudinally with respect to the stack-receiving belt. The last-discussed feature enables an optimum positioning of the stacker for receiving sheets from a slottcr, printing press or the like without disturbing the stack-receiving belt.

The preferred embodiment of the invention will now be discussed in detail with reference being made to the drawing which constitutes an elevational view partially in section with parts removed for clarity.

A floor or other horizontal supporting surface 1 is provided in supporting relationship to the preferred embodiment of the subject inventive automatic stacker. The stacker includes a pair of spaced sideplates 2 (only one of which is shown in the drawing) forming a main frame means which provides support for the remaining stacker elements. A stack-supporting fixed frame 5 resting on surface 1 (by support means not shown) is mounted adjacent the left side of frame plate 2 and includes movable belt means B for receiving the deposited sheets in a manner to be discussed in detail hereinafter.

A pair of longitudinally extending frame members 6 (only one of which is illustrated in the drawing) are pivotally connected to the sideplates 2 by means of a shaft 7. Frame members 6 provide support for a conventional belt-type conveyor of the exact type shown in the parent application Ser. No. 743,419 extending the length of the frame member 6 and being supported by a downstream roller 8' and an upstream roller that is concentric with and fixed to the shaft 7. The conveyor system mounted on frame members 6 is essentially identical to the conveyor employed in the parent application.

ln any event, the frame members 6 pivot about shaft 7 so that the head, or sheet discharge, portion 8 of the conveyor on frames 6 is movable along an arcuate path between the various positions as shown in the drawing.

Cross frame members 9, 10, 11 and 12 extend between the sideplate 2 and rigidly connect the plates 2 to provide a strong unitary structure. Two hydraulic jacks 14 (only one of which is shown in the drawing) are pivotally connected to the cross frame 10 at 13 and each has a piston rod 16 extending from its other end for pivotal connection to one of the beams 6 at 15.

A connecting link 17 is pivotally connected at 18 to the beams 6. Moreover, the other end of link 17 is connected to a shaft 19 on which a supporting roller 20 is mounted for rotation. Roller 20 is positioned between an upper guide 22 and a lower guide 21 which limits movement of roller 20 to horizontal movement in an obvious manner. An L-shaped lever comprising a vertical arm 23 and a horizontal arm 24 is mounted so that the upper end of the vertical arm 23 is pivotally connected to the shaft 19. Consequently, horizontal displacement of the roller 20 and associated shaft 19 serves to displace the arms 23 and 24 in like manner.

A pressure friction drive roller 25 formed of rubber of the like and of cylindrical shape is supported on the horizontal arm 24 for rotation about its axis and is connected to a conventional speed reducing gear brake device 26 by means of a chain 27. Consequently, operation of a motor M drivingly connected to the gear reducer and braking device 26 can serve to rotate the pressure roller 25. Moreover, actuation of the brake portion of the gear reducer brake device 26 automatically occurs when motor M is not activated and serves to immobilize the roller 25 to prevent any rotation thereof.

The stack-supporting frame 5 includes a plurality of idler rollers 28 mounted for rotation on the frame and which support the upper flight 29 of the endless conveyor belt B which extends over and about the rollers. A brake 30 is mounted adjacent one end of the belt B and has a brake shoe 32 engageable with an end of the conveyor belt B for stopping and preventing movement of the conveyor belt if such should be desired. The braking member 30 is preferably pneumatically operated. However, this device can also be actuated either mechanically or electrically if such should be desired. Additionally, cross frame member 12 supports a pneumatically operated stacker braking device 31 which, when operated, serves to engage the floor or supporting surface 1 for preventing movement of the frames 2 and their associated supported structure with respect tothe supporting surface 1. Here again, the braking member 31 is preferably pneumatically operated but could be operated mechanically or electrically if such should be desired. Stacker brake 31 is normally actuated for maintaining the stacker in fixed position.

The conveyor supporting frame members 6 are mounted for pivotal movement about the axis of shaft 7 so that the discharge end or head 8 of the conveyor moves in an arcuate path P. The arcuate path P has a maximum sagitta in the horizontal plane H as shown in the drawing. If sheets were merely deposited from the conveyor on frames 6, the resultant stack would obviously have a side edge parallel to the arcuate path P. However, it is obviously undesirable for such stacks to be provided and the preferred embodiment avoids the forma tion of a curved stack by shifting the position of the stack-sup porting belt B during the stacking operation to always maintain the discharge end of the conveyor and a point on the belt B in fixed vertical alignment with respect to each other. In other words, there is absolutely no horizontal movement of the belt B with respect to the discharge end of the conveyor.

It should be noted that a stacking operation initially begins with the discharge end of the conveyor being in the position 8 shown in the drawing. However, as the stack moves vertically upward, the cylinder 14 is actuated to pivot the frame members 6 in a clockwise direction as shown in the drawing. Such pivotal movement of the frame member 6 causes the connection point 18 to shift link 17 and roller 20 along with shaft 19 to consequently move the horizontal arm 24 in a horizontal direction to keep the stack supporting belt B (roller 25 being locked against rotation) in aligned relationship with the discharge end of the conveyor supported on frames 6. The shifting movement of the carriage is enabled by virtue of the fact that the brake member 26 is locked and the frictional engagement of pressure roller 25 with the upper surface of the belt B consequently serves to displace the upper flight of the belt by virtue of the fact that the belt is supported by idler rollers 28. Therefore, the carriage frame members 5 do not actually move; however, the upper flight of the belt is shifted to maintain the discharge portion of the belt in exact aligned relationship at all times with the discharge end of the stacking conveyor supported by frame elements 6. The dimensions of the parts are such as to always maintain this relationship.

Any displacement of the head 8 of the conveyor elevating frame assembly 6 is obviously associated with an identical horizontal displacement of roller 19, which is conveyed by means of arms 23 and 24 to pressure roller 25 which transmits same to the displaceable belt flight 29. Consequently, the pile always remains in vertical alignment with the discharge from the conveyor supported by frame elements 6.

Arrival of the conveyor frame at the uppermost extent of its movement illustrated in the drawing serves to actuate the motor M of the gear reducer braking device 26 by means of a microswitch or other suitable means (not shown) so that the motor M is started and the brake is released to permit the roller 25 to actuate the belt B to move the stacked pile in the direction indicated by arrow P away from the stacked position. Stacker holding brake 31 is activated during this operation for holding the stacker in position. The stack can be conveyed to another conveyor or other desired apparatus.

After the stack is removed, the pneumatic belt locking brake means 30 is actuated to move the shoe 32 into engagement with the belt B in an obvious manner. Motor M is operated in a reverse direction and hydraulic jack 14 is actuated to lower the frame members 6 to their lowermost stack initiating position. The device is then in a position to begin another stacking operation.

When the preferred embodiment as shown in the drawing is employed with a processing machine such as a slotter, printing machine or the like, it is a relatively simple matter to position the stacker for proper discharge of sheets from the processing machine. However, the stacker can easily be retained in position by actuation of brake 31 etc. One great advantage of the preferred embodiment is that the position of the sheet stacker 2, 6 etc., is easily adjusted with respect to the belt B to be positioned at any desired point along the length of belt B. For example, actuation of the brake shoe 30 serves to lock the belt B and subsequent actuation of motor M, with brake 31 being deactivated, will drive the roller 25 to consequently shift plates 5, frame 6 and the entire structure supported by rollers 3 and 4 with respect to belt B and frame 5. Since motor M is reversible, the relative position of the stack support 5, etc., and the stacker is adjustable in either direction. In other words, since the stack-supporting frame member 5 is fixed to the ground 1, the brake 31 can be released so that actuation of rollers 25 in the last mentioned manner will serve to shift roller 25, elements 24, 23 and frames 2 etc., with respect to the support 1 and the stack-receiving member 5 in an obvious manner. In fact, the stacker assembly 2, 6 etc., can be positioned at any point along the length of the belt B. This is true because the transversely extending cross frame members 9, l0, l1 and 12 are positioned in a horizontal plane above the upper fight 29 of belt B.

It should be understood that many modifications of the subject invention will occur to those skilled in the art; however, the invention should be limited solely by the appended claims.

Iclaim:

l. A sheet stacker comprising a main frame means, a horizontally extending pivot shaft attached to said frame means, an elongated driven feed conveyor mounted on a conveyor support frame pivotally connected on its infeed end to said pivot shaft, power actuated conveyor adjusting means or adjustably positioning said conveyor about said pivot means for adjusting the vertical height of the downstream end of said sheet conveyor and a freely movable stack receiving and removing conveyor belt having a horizontal upper flight upon which sheets are deposited by said sheet feed conveyor at a stacking location, a fixed frame upon which said stack receiving and removing conveyor belt is freely mounted for movement with respect thereto, linkage control means connecting said stack-receiving and removing conveyor belt and said sheet feed conveyor for actuating said stack-receiving conveyor belt to move the upper flight of said stack-receiving conveyor belt with respect to said fixed frame upon which said belt is mounted to maintain corresponding portions of said upper flight of said stack receiving conveyor in vertical alignment with the downstream end of said sheet conveyor for all vertical positions of the downstream end of said sheet conveyor whereby sheets deposited from said sheet conveyor onto said stack receiving conveyor belt are oriented in vertical alignment to provide a vertical stack.

2. The invention of claim 1 wherein said means for pivoting said sheet feed conveyor comprises pneumatic jack means connected on one end to said frame means and on the other end to said sheet feed conveyor support frame.

3. The invention of claim 2 wherein said linkage control means includes a motor, a gear reducer brake device driven by said motor when said motor is actuated but automatically locked in fixed position upon deactivation of said motor, transmission means connecting said gear reducer brake device to a friction drive roller engageable with said power receiving belt whereby actuation of said motor rotates said friction power roller to move said power receiving belt in a desired direction to convey a completed stack away from the stacking location.

4. The invention of claim 3 wherein said friction drive roller is mounted on bodily movable support means which when moved during deactivation of said motor and consequent roller rotation preventing locking action of said gear reducer brake device serves to shift said stack receiving upper flight of said stack receiving belt with respect to said fixed frame upon which said stack receiving belt is mounted.

5. The invention of claim 4 wherein said linkage control means additionally includes an L-shaped member having a horizontal arm constituting said bodily movable support means upon which said motor and friction drive roller are mounted and a vertical arm having a roller at its upper end, guide means mounted on said main frame means and associated with said roller at the upper end of said vertical arm for limiting the path of movement of said roller to a horizontal path of movement and link means connecting said roller to said sheet conveyor whereby pivotal movement of said sheet conveyor serves to move said roller along said horizontal path.

6. The invention of claim 5 additionally including selectively operable belt locking brake means for preventing movement of said stack-receiving conveyor belt with respect to the fixed frame upon which said stack-receiving conveyor is mounted and wheels supporting said main frame means for movement over its supporting surface whereby said main frame means can be shifted along the length of said stack receiving and removing conveyor belt upon actuation of said belt locking brake means and subsequent motor driven rotation of said friction drive roller.

7. The invention of claim 6 additionally including main frame mounted stacker locking support surface engaging brake means for preventing relative movement of said frame with respect to its supporting surface.

8. The invention of claim 7 wherein said friction drive roller is gravitationally biassed into contact with the upper flight of said stack receiving and removing conveyor belt.

9. The invention of claim 8 wherein said roller guide means comprises upper and lower horizontally extending guide plates fixed to said main frame means.

10. The invention of claim 9 wherein said stack receiving and removing conveyor belt is supported upon said fixed frame by a plurality of idler rollers fixed to said fixed frame. 

1. A sheet stacker comprising a main frame means, a horizontally extending pivot shaft attached to said frame means, an elongated driven feed conveyor mounted on a conveyor support frame pivotally connected on its infeed end to said pivot shaft, power actuated conveyor adjusting means or adjustably positioning said conveyor about said pivot means for adjusting the vertical height of the downstream end of said sheet conveyor and a freely movable stack receiving and removing conveyor belt having a horizontal upper flight upon which sheets are deposited by said sheet feed conveyor at a stacking location, a fixed frame upon which said stack receiving and removing conveyor belt is freely mounted for movement with respect thereto, linkage control means connecting said stack-receiving and removing conveyor belt and said sheet feed conveyor for actuating said stack-receiving conveyor belt to move the upper flight of said stack-receiving conveyor belt with respect to said fixed frame upon which said belt is mounted to maintain corresponding portions of said upper flight of said stack receiving conveyor in vertical alignment with the downstream end of said sheet conveyor for all vertical positions of the downstream end of said sheet conveyor whereby sheets deposited from said sheet conveyor onto said stack receiving conveyor belt are oriented in vertical alignment to provide a vertical stack.
 2. The invention of claim 1 wherein said means for pivoting said sheet feed conveyor comprises pneumatic jack means connected on one end to said frame means and on the other end to said sheet feed conveyor support frame.
 3. The invention of claim 2 wherein said linkage control means includes a motor, a gear reducer brake device driven by said motor when said motor is actuated but automatically locked in fixed position upon deactivation of said motor, transmission means connecting said gear reducer brake device to a friction drive roller engageable with said power receiving belt whereby actuation of said motor rotates said friction power roller to move said power receiving belt in a desired direction to convey a completed stack away from the stacking location.
 4. The invention of claim 3 wherein said friction drive roller is mounted on bodily movable support means which when moved during deactivation of said motor and consequent roller rotation preventing locking action of said gear reducer brake device serves to shift said stack receiving upper flight of said stack receiving belt with respect to said fixed frame upon which said stack receiving belt is mounted.
 5. The invention of claim 4 wherein said linkage control means additionally includes an L-shaped member having a horizontal arm constituting said bodily movable support means upon which said motor and friction drive roller are mounted and a vertical arm having a roller at its upper end, guide means mounted on said main frame means and associated with said roller at the upper end of said vertical arm for limiting the path of movement of said roller to a horizontal path of movement and link means connecting said roller to said sheet conveyor whereby pivotal movement of said sheet conveyor serves to move said roller along said horizontal path.
 6. The invention of claim 5 additionally including selectively operable belt locking brake means for preventing movement of said stack-receiving conveyor belt with respect to the fixed frame upon which said stack-receiving conveyor is mounted and wheels supporting said main frame means for movement over its supporting surface whereby said main frame means can be shifted along the length of said stack receiving and removing conveyor belt upon actuation of said belt locking brake means and subsequent motor driven rotation of said friction drive roller.
 7. The invention of claim 6 additionally including main frame mounted stacker locking support surface engaging brake means for preventing relative movement of said frame with respect to its supporting surface.
 8. The invention of claim 7 wherein said friction drive roller is gravitationally biassed into contact with the upper flight of said stack receiving and removing conveyor belt.
 9. The invention of claim 8 wherein said roller guide means comprises upper and lower horizontally extending guide plates fixed to said main frame means.
 10. The invention of claim 9 wherein said stack receiving and removing conveyor belt is supported upon said fixed frame by a plurality of idler rollers fixed to said fixed frame. 